Table 3. .

Summary of Marker Information^[Note]

Gene Name and SNP or Deletion	Gene/SNP Designation	Allele Frequencya (%)	Functional Effects of Variantsb
Aryl hydrocarbon receptor:
G1721A	AHR_snp1	7	Higher inducibility for CYP1A1
A→G	AHR_snp2	31	Unknown
Cytochrome P450 1A1:
T3801C	CYP1A1c	7	Stabler mRNA, higher activity
Cytochrome P450 1A2:
−164C→A in intron 1	CYP1A2c	32	Lower activity
Cytochrome P450 1B1:
Val432Leu	CYP1B1_snp1	49	Lower activity
Asn453Ser	CYP1B1_snp2	15	Unknown
Cytochrome P450 2E1:
G→A	CYP2E1	21	Unknown
Microsomal epoxide hydrolase:
Y113H	EPHX1_snp1c	32	Higher activity
His139Arg	EPHX1_snp2	22	Higher activity
Glutathione transferases alpha-4:
G→C	GSTA4_snp1	41	Unknown
T→C	GSTA4_snp2	27	Unknown
Glutathione transferases mu-1:
Null deletion	GSTM1_nullc	56	Loss of function
C→G	GSTM1_snp1	37	Unknown
Glutathione transferases mu-3:
G→A	GSTM3	37	Unknown
Glutathione transferases pi-1:
A313G	GSTP1_snp1c	38	Lower activity
C341T	GSTP1_snp2	10	Unknown
G→T	GSTP1_snp3	46	Unknown
Glutathione transferases theta-1:
Null deletion	GSTT1_nullc	18	Loss of function
Hypoxia-induced factor-1 alpha subunit:
A→C	HIF1A	25	Unknown
N-acetyltransferases (NATs) 2:
C481T	NAT2_snp1c	41	Unknown
G590A	NAT2_snp2c	33	Lower activity
NAD(P)H: quinone oxidoreductase:
C609 T	NQO1c	17	Loss of function
Sulfotransferases 1A1:
R213H	SULT1A1	38	Lower activity
UDP-glucuronosyltransferases 1A7:
T387G, C391A, and G392A	UGT1A7_snp1	63	Unknown
T662C	UGT1A7_snp2	36	Unknown

Note.— The SNP designations are used in other tables as references to markers.

^aAllele frequencies were based on Iowan control samples.

^bChange in enzymatic activities of the variant allele (the second allele listed in SNP column).

^cOnly these markers were genotyped on the DBS samples.